Visual Composer will work with pretty much every theme, but any pages/post you already created with Live Composer will NOT automatically transfer to Visual Composer. Both page builders use different shortcodes for their rows and columns, as well as content elements, so the shortcodes used in Live Composer won’t render with Visual Composer, and vice versa.

It is usually best, to start with new/blank pages/post when switching page builders and you also should NOT activate both page builders at the same time, and instead settle on one, even if that means that you have to recreate existing pages/posts.

By using this plugin you can be sure to not be locked with page builder if you want to change theme in the future. All the pages and most of the styling will stay as it is. You will not need to buy a new license like with Visual Composer (extra $34) and can be sure the plugin is actively developed and maintained by WordPress community.